Blackie- I would suggest slugging BOTH ends to see if there is any taper, and also push a slug all the way hrough from the breech to see if there are any tight or loose spots in the bore.

Willis ??? ???

Blacki,

  You're right in not spending a lot of money on something that might be shot out. Your best bet right now is to clean the rifle and to make sure all the fouling and Leading is out, and then proceed with taking measurements as suggested by Willis.

  I'm not familiar with this model rifle, but one thing to remember is that a lot of these old military cartridge rifles never had very deep rifling to begin with. With BP there is no real reason for it.

  I guess I don't understand your muzzle dim. of .3125" and then you say a slug measured .437. Even if you misprinted the first dim. and it's really .4125" this would make for some very deep rifling. You don't mention if the slug was pushed all the way thru, or just an inch or so into the muzzle.... or breech, and then pushed back out.

  With the info you've given us it's hard to give advice. So... Relax! Take your time and do what's been suggested in the proper order and manner. Most likely things will become pretty well self-evident. But, if not report back with some useful information and I'm sure someone will be able to help you with any questions. We're not going anywhere!

PETE

Blacki,

The advice I am giving may seem a bit harsh, but here it is.  I personally would not  invest anything into a military rolling block in .43 spanish, not cases, dies, or molds.  I wouldn't even invest in the time to try to work with it if I was given the dies, mold and cases.

Over the past few years I have seen this question and discussion at least a dozen times.  The people that have tried it before have said "rebarrel it to a reasonable caliber, in the long run you'll be happier."   Several of the posters have gone ahead anyway, and a few months or a couple of years later, they post that they have a project where they're rebarreling a .43 spanish to something else, and want to sell dies, brass, molds.

Generally, military rolling blocks have barrels that won't shoot well.  The muzzle is usually worn funnel shaped from cleaning rods, and the pitting/wear/problems in the bore preclude fine accuracy.  The .43 spanish is a somewhat difficult round to load accurately anyway.  Combine all this together, and you're on a quick road to failure.   

I work on rolling blocks a bit.  When I get a .43, I throw the barrel away, don't even waste the time to ebay it.  I think it's a disservice to perpetuate the misery!  I'd personally rebarrel to .45-XX (fill in the x's with 70 or 90) and never look back.  Dies, brass, bullets, etc are readily available and cheap, which they aren't for the .43.  The savings in mold, dies, brass will almost pay for the rebarrel and you'll have a guaranteed shooter.

For what it's worth......

dave

Pete,
I recleaned the bore multiple times. I can now see rifling so I reslugged the bore with a .439 lead bullet. The bullet drops into the breech end without any problems ( too loose I think ) but it comes to a dead stop about 6 inches from the muzzel end. When pushed through and measured it measures out at .4375. Now is a .439 bullet going to be able to be fired through this area ( muzzel end of barrel is .0015" narrower than breech end ) assuming obturation of the bullet upon firing??? Any thoughts?
Thanks
Blacki

The bore at the very begining of the rifling measures .4687, did a chamber cast.Yes it will be B.P.
Blacki

I am most curious about the chamber shape & measurements.  Blacki, was it a bottlenecked chamber or a straight taper?  Would you please post the chamber measurements?  Thanks.

FWIW, I think the advice about a new barrel is good if you intend to do a lot of serious shooting with your old RB, but begin with the end in mind.  It is easy to get more $ into those old military rifles than they are worth.  I have an 1886 Kropatschek with a lot of time & TLC invested in it.  Also a set of 4-D dies and cases made from .348 brass and every time I look at the old Krop, I wonder what I was thinking about.  My late friend & I had a lot of fun restoring the old  dog, with attendant cheap red wine & $2 cigars, but the memories are worth a lot more than the rifle.

I think Cartridges of the World is wrong with the Reformado history.  The Reformado cartridge apparently originated in Spain when they could not get those 11mms to shoot accurately (to mil. stds) when they were new.  They blamed bottlenecked cases. So reamed out the chambers & apparently enough of the breech end to swallow a big brass-jacketed bullet.  I don't know why the Spanish had problems and the Argentinians did not.  All the Reformado cartridges I have seen have Spanish headstamps and dates from the 1890s.

I do not know where you would find Reformado brass, and that rim measurement says you might think about headspace.  But if you had 1 or 2 cases, you might be able to breechseat a lead .45 bullet and at least find out if the barrel has any potential as a plinker.